[MAXscript] Storing Multiclass array

If you would like to store “Multi-class array” within the object (scripted material/modifier/… plugin), how you would solve that?
Parameters doesn’t allow to have data/class like #(20,“String”,2.2,#(“a”,1))

Any ideas if it is even possible in MAX?

Serialize the array to XML or JSON and store it as a string.

Of course you’ll have to wrangle some Dot Net functionality and possibly add functions to your Custom attribute to pack and unpack the data…
Personally, would use JSON for this.
I wrote a Max script struct for utilizing JSON.net a while back you can find it here

If you have a more recent 3DS Max version you should probably use Python to pack your JSON data into a string and then Max script for your attribute